Ultrasound doppler applicator

ABSTRACT

An ultrasound Doppler applicator is used for determining the movement of internal body parts the position of which is variable relatively to the applicator, particularly fetal heart movement. The invention is particularly characterized by the provision of a plurality of ultra sound sending oscillators and a plurality of ultra sound receiving oscillators carried by a ring and distributed over the entire ring.

United States Patent [191 Soldner et al.

[ 1 July 23, 1974 1 1 ULTRASOUND DOPPLER APPLICATOR [75] Inventors:Richard Soldner, Erlangen; Gerhard Naefe, Erlangen-bruck, both ofGermany [73] Assignee: Siemens Aktiengesellschatt,

Erlangen, Germany 22 Filed: Jan. 30, 1973 21 Appl. No.: 328,147

[30] Foreign Application Priority Data Jan. 31, 1972 Germany 22004474[52] US. Cl 128/2 V [51] Int. Cl A6lb 5/00 [58] Field of Search 128/2 R,2 V, 24 A, 303

[56] References Cited UNITED STATES PATENTS 3,156,110 11/1964 Clynes128/2 V OTHER PUBLICATIONS Wells, Med. & Biol. Engng. Vol. 8, 1970, pp.241-256 Flaherty et al 128/2 V Larson et al l28/2 V PrimaryExaminer-Lawrence W. Trapp Attorney, Agent, or F irm- Richards 8L Geierand V. Alexander Scher [5 7] ABSTRACT An ultrasound Doppler applicatoris used for determining the movement of internal body parts the positionof which is variable relatively to the applicator, particularly fetalheart movement. The invention is particularly characterized by theprovision of a plurality of ultra sound sending oscillators and aplurality of ultra sound receiving oscillators carried by a ring anddistributed over the entire ring.

12 Claims, 4 Drawing Figures 1 ULTRASOUND DOPPLER APPLICATOR Thisinvention relates to an ultrasound Doppler applicator determining themovement of internal body parts the position of which is variablerelatively to the applicator, particularly fetal heart movement.

Known applicators of this type are used for determining fetal heartmovements. The simplest applicator consists of two oscillators locatedclose to each other, one of which functions as a sender and the other asa receiver. Such an applicator has a comparatively sharpsending-receiving directional characteristic and is therefore not wellsuited for continuous supervision of fetal heart movement, since bymovement of the fetus its heart can easily leave the range of the sound.Furthermore, the signal output is comparatively small, since thereceiving oscillator actually gets only echo signals from reflectionsurfaces perpendicular to the flow direction of the sound.

Another known applicator has a flat disc serving as a carrier forseveral receiving oscillators arranged in a concentric circle about acentral sending oscillator. This applicator makes possible the coverageof the entire possible movement range of the fetus and it also producesa higher signal output since the receiving oscillators grouped aroundthe sending oscillator also register echo signals from surfaces with acertain inclination. However, there are difficulties in coupling theindividual oscillators to the body surface of the person, since theflat, rigid disc with comparatively large surface is difficult to adaptto a body surface with different curvatures. 1

An object of the present invention is to provide an applicator whichwill also cover the entire movement range of the fetus but, as comparedto prior art, will have a greater increase in signal output and at thesame time can be coupled in a much simpler and safer manner to verycurved body surfaces.

Other objects of the present invention will become apparent in thecourse of the following specification.

In the accomplishment of the objectives of the present invention it wasfound desirable to provide a ring carrying a plurality of ultra soundsending oscillators and a plurality of ultra sound receivingoscillators, the oscillators being distributed over the entire ring.

A ring can be much better adapted to curved soft surfaces than a disc.The increased adaptability of the oscillator carrier provides a betterand less critical coupling of the individual oscillators to the curvedbody surface. Furthermore, a plurality of ultra sound sendingoscillators located outside of the application center provide a muchbetter space illumination of the object being examined (fetus hearts),with the result that the signal output will be further increased by asubstantial amount.

According to an advantageous embodiment of the present invention theindividual sending oscillators and receiving oscillators are arrangedalternately upon the ring in a circle which is concentrical to thecenter of the ring. The distances between the oscillators are madeequal.

.According to a particularly effective embodiment of the presentinvention a total of three sending oscillators and three receivingoscillators, each having a diameter of about 8 mm, ismounted upon a ringhaving an average diameter of about 50 mm. Such an applicator providesbest receiving conditions for echo signals from a depth range of about 6cm to 12 cm, namely, specifically for echo signals coming from the heartof the fetus (average distance of fetus from body surface is about 8cm).

According to a further advantageous development of the present inventionthere is also provided a pressure changer, for example, a pressureballoon, fitting into the interior of the ring, for simultaneouslyreceiving the tocogram of the circular ends. The ring can be the memberreceiving the pressure changer or it can be a component part of thecasing of the pressure changer.

The invention will appear more clearly from the following detaileddescription when taken in connection with the accompanying drawingshowing by way of example only, preferred embodiments of the inventiveidea.

In the drawing:

FIG. 1 is a front view of an ultrasound Doppler applicator.

FIG. 1a is a section along the line A A of FIG. 1.

FIG. 2 is a front view of an applicator combined in a tocogram receiver.

FIG. 2a is a section along the line B B of FIG. 2.

The ultrasound Doppler applicator for determining fetal heart movementsshown from the application side in FIG. 1, includes a total of threeultrasound sending oscillators 1, 2 and 3 and three receivingoscillators 4, 5 and 6 consisting of piezoelectrical crystal plates witha diameter of about 8 mm. The oscillators are arranged as an alternatingrow upon a carrier member 7 having hollow spaces 7 for receiving theoscillators. The carrier member 7 has an application surface 8 and acover 9 which can be screwed on. Thus these parts form a ring 10 made ofpolystyrol. The average diameter of the ring 10 amounts to 50 mm, itswidth is 9 mm and its total thickness is 10 mm.

The individual sending and receiving oscillators are electricallyconnected in parallel and work in continuous stroke or impulseoperation. Electrical conduits 11 and 12 are connecting lines of theindividual sending oscillators or receiving oscillators with sendinghigh frequency generator or Doppler device for indicating Dopplersignals (both not shown).

An applicator combined with a tocogram receiver 13 is shown again fromthe application side in FIG. 2.

The tocogram receiver 13 consists of a pressure balloon 14 inserted intothe round interior of the disc 10 and having a rigid casing part 15 anda balloon membrane 16. The balloon 14 can be blown up by a pump (notshown) connected to' apressure conduit 17 to a desired volume orpressure value. The conduit 17 also carries a mechanical-electricalpressure changer (not shown) for changing pressure variations in theballoon 14 into corresponding electrical signals (tocogram).

The described ultrasound Doppler applicator is used as follows:

The ring 10 is applied, for example, by means of an adhesive plaster tothe stomach in such manner that the individual sending and receivingoscillators are in good contact with the skin. The ultrasound wavesemitted by the senders 1 to 3 are among others, reflected by the fetusheart and the reflected waves are transformed in the receivingoscillators 4 to 6 into corresponding electrical signals. The frequencydeviations resulting from 3' heart movements between the sent out ultrasound and the received ultra sound produce Doppler signals constitutinga measure for the heart movementsof the fetus. The heart frequency ofthe fetus can be determined directly from the following frequency of theappearing Doppler signals.

According to FIGS. 2 and 2a to the heart movements of the fetus is alsoadded the tocogram, namely the contraction signal of the woman. For thatpurpose the balloon 14 blown to a specific volume or pressure value, ispressed into the interior of the ring so that the diaphragm 16 pressesagainst the stomach of the woman.

If uterus contractions take place, they are received as pressurevariations in the balloon 14 and are transmitted by the pressure conduit17 to the mechanicalelectrical pressure changer.

What is claimed is:

1. An ultrasound Doppler applicator for determining which are moveablerelatively to the applicator, particularly fetal heart movements, saidapplicator comprising a ring and a plurality of ultrasound sendingoscillators and ultrasound receiving oscillators carried by said ring,said oscillators being distributed throughout the entire ring.

2. An applicator in accordance with claim 1, wherein the individualsending and receiving oscillators are mounted alternately upon said ringalong a circle concentric to the center of said ring.

3. An applicator in accordance with claim 2, wherein the movements ofinternal body parts the locations of 20 i 4 the distances between theapplicators are equal.

4. An applicator in accordance with claim 3, wherein there are threesending oscillators and three receiving oscillators, each oscillatorhaving a diameter of substantially 8 mm, said ring having an averagediameter of substantially 50 mm.

5. An applicator in accordance with claim 4, wherein the width of saidring is substantially 10 mm.

6. An applicator in accordance with claim 1, wherein said ring compriseshollow spaces receiving said oscillators.

7. An applicator in accordance with claim 1, comprising means connectingthe individual sending oscillators and receiving oscillatorselectrically in parallel.

8. An applicator in accordance with claim 1, wherein said ring consistsof an artificial material, preferably polystyrol.

9. An applicator in accordance with claim 1, wherein said ring is a discring.

10. An applicator in accordance with claim 1, comprising a pressurechanger fitting into the interior of said ring for receiving a tocogramof an expectant mother.

11. An applicator in accordance with claim 10, wherein said ringencloses and holds said pressure changer.

12. An applicator in accordance with claim 10, wherein said pressurechanger has a casing, said ring being a part of said casing.

1. An ultrasound Doppler applicator for determining the movements ofinternal body parts the locations of which are moveable relatively tothe applicator, particularly fetal heart movements, said applicatorcomprising a ring and a plurality of ultrasound sending oscillators andultrasound receiving oscillators carried by said ring, said oscillatorsbeing distributed throughout the entire ring.
 2. An applicator inaccordance with claim 1, wherein the individual sending and receivingoscillators are mounted alternately upon said ring along a circleconcentric to the center of said ring.
 3. An applicator in accordancewith claim 2, wherein the distances between the applicators are equal.4. An applicator in accordance with claim 3, wherein there are threesending oscillators and three receiving oscillators, each oscillatorhaving a diameter of substantially 8 mm, said ring having an averagediameter of substantially 50 mm.
 5. An applicator in accordance withclaim 4, wherein the width of said ring is substantially 10 mm.
 6. Anapplicator in accordance with claim 1, wherein said ring compriseshollow spaces receiving said oscillators.
 7. An applicator in accordancewith claim 1, comprising means connecting the individual sendingoscillators and receiving oscillators electrically in parallel.
 8. Anapplicator in accordance with claim 1, wherein said ring consists of anartificial material, preferably polystyrol.
 9. An applicator inaccordance with claim 1, wherein said ring is a disc ring.
 10. Anapplicator in accordance with claim 1, comprising a pressure changerfitting into the interior of said ring for receiving a tocogram of anexpectant mother.
 11. An applicator in accordance with claim 10, whereinsaid ring encloses and holds said pressure changer.
 12. An applicator inaccordance with claim 10, wherein said pressure changer has a casing,said ring being a part of said casing.